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1public class AESFileEncryption {
2public static void main(String[] args) throws Exception {
3
4    // file to be encrypted
5    FileInputStream inFile = new FileInputStream("plainfile.txt");
6
7    // encrypted file
8    FileOutputStream outFile = new FileOutputStream("encryptedfile.des");
9
10    // password to encrypt the file
11    String password = "javapapers";
12
13    // password, iv and salt should be transferred to the other end
14    // in a secure manner
15
16    // salt is used for encoding
17    // writing it to a file
18    // salt should be transferred to the recipient securely
19    // for decryption
20    byte[] salt = new byte[8];
21    SecureRandom secureRandom = new SecureRandom();
22    secureRandom.nextBytes(salt);
23    FileOutputStream saltOutFile = new FileOutputStream("salt.enc");
24    saltOutFile.write(salt);
25    saltOutFile.close();
26
27    SecretKeyFactory factory = SecretKeyFactory
28            .getInstance("PBKDF2WithHmacSHA1");
29    KeySpec keySpec = new PBEKeySpec(password.toCharArray(), salt, 65536,
30            256);
31    SecretKey secretKey = factory.generateSecret(keySpec);
32    SecretKey secret = new SecretKeySpec(secretKey.getEncoded(), "AES");
33
34    //
35    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
36    cipher.init(Cipher.ENCRYPT_MODE, secret);
37    AlgorithmParameters params = cipher.getParameters();
38
39    // iv adds randomness to the text and just makes the mechanism more
40    // secure
41    // used while initializing the cipher
42    // file to store the iv
43    FileOutputStream ivOutFile = new FileOutputStream("iv.enc");
44    byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
45    ivOutFile.write(iv);
46    ivOutFile.close();
47
48    //file encryption
49    byte[] input = new byte[64];
50    int bytesRead;
51
52    while ((bytesRead = inFile.read(input)) != -1) {
53        byte[] output = cipher.update(input, 0, bytesRead);
54        if (output != null)
55            outFile.write(output);
56    }
57
58    byte[] output = cipher.doFinal();
59    if (output != null)
60        outFile.write(output);
61
62    inFile.close();
63    outFile.flush();
64    outFile.close();
65
66    System.out.println("File Encrypted.");
67
68}